Passive multi-unit field-pilot for acid mine drainage remediation: Performance and environmental assessment of post-treatment solid waste.

This study evaluated the performance of a passive multi-unit field-pilot operating for 16 months to treat acid mine drainage (AMD) from a coal mine in Colombia Andean Paramo. The multi-unit field-pilot involved a combination of a pre-treatment unit (550 L) filled with dispersed alkaline substrate (DAS), and six passive biochemical reactors (PBRs; 220 L) under two configurations: open (PBRs-A) and closed (PBRs-B) to the atmosphere. The AMD quality was 1200 ± 91 mg L Fe, 38.

Powder and Nanotubes Titania Modified by Dye Sensitization as Photocatalysts for the Organic Pollutants Elimination.

In this study, titanium dioxide powder obtained by the sol-gel method and TiO₂ nanotubes, were prepared. In order to increase the TiO₂ photoactivity, the powders and nanotubes obtained were modified by dye sensitization treatment during the oxide synthesis. The sensitizers applied were Quinizarin (Q) and Zinc protoporphyrin (P).

Effect of the substrate and catalyst chirality on the diastereoselective epoxidation of limonene using Jacobsen-type catalysts.

Chiral and achiral Jacobsen's catalysts in their homogeneous form or immobilized on Al-MCM-41 exhibit similar catalytic activity during diastereoselective epoxidation of limonene when in situ generated dimethyldioxirane is used as oxidizing agent. Experimental observations suggest that not only the catalyst chiral center but also the substrate chiral center participates in the preferential formation of most diastereomers. Remarkable turnover numbers (TON), up to 288, was achieved over the heterogeneous catalysts in comparison to their homogeneous counterparts (TON up to 46).